include/linux/nfs_page.h

   1 /*
   2  * linux/include/linux/nfs_page.h
   3  *
   4  * Copyright (C) 2000 Trond Myklebust
   5  *
   6  * NFS page cache wrapper.
   7  */
   8
   9 #ifndef _LINUX_NFS_PAGE_H
  10 #define _LINUX_NFS_PAGE_H
  11
  12
  13 #include <linux/list.h>
  14 #include <linux/pagemap.h>
  15 #include <linux/wait.h>
  16 #include <linux/sunrpc/auth.h>
  17 #include <linux/nfs_xdr.h>
  18
  19 #include <linux/kref.h>
  20
  21 /*
  22  * Valid flags for the radix tree
  23  */
  24 #define NFS_PAGE_TAG_LOCKED     0
  25 #define NFS_PAGE_TAG_COMMIT     1
  26
  27 /*
  28  * Valid flags for a dirty buffer
  29  */
  30 enum {
  31         PG_BUSY = 0,
  32         PG_CLEAN,
  33         PG_NEED_COMMIT,
  34         PG_NEED_RESCHED,
  35 };
  36
  37 struct nfs_inode;
  38 struct nfs_page {
  39         struct list_head        wb_list;        /* Defines state of page: */
  40         struct page             *wb_page;       /* page to read in/write out */
  41         struct nfs_open_context *wb_context;    /* File state context info */
  42         struct nfs_lock_context *wb_lock_context;       /* lock context info */
  43         atomic_t                wb_complete;    /* i/os we're waiting for */
  44         pgoff_t                 wb_index;       /* Offset >> PAGE_CACHE_SHIFT */
  45         unsigned int            wb_offset,      /* Offset & ~PAGE_CACHE_MASK */
  46                                 wb_pgbase,      /* Start of page data */
  47                                 wb_bytes;       /* Length of request */
  48         struct kref             wb_kref;        /* reference count */
  49         unsigned long           wb_flags;
  50         struct nfs_writeverf    wb_verf;        /* Commit cookie */
  51 };
  52
  53 struct nfs_pageio_descriptor {
  54         struct list_head        pg_list;
  55         unsigned long           pg_bytes_written;
  56         size_t                  pg_count;
  57         size_t                  pg_bsize;
  58         unsigned int            pg_base;
  59
  60         struct inode            *pg_inode;
  61         int                     (*pg_doio)(struct inode *, struct list_head *, unsigned int, size_t, int);
  62         int                     pg_ioflags;
  63         int                     pg_error;
  64 };
  65
  66 #define NFS_WBACK_BUSY(req)     (test_bit(PG_BUSY,&(req)->wb_flags))
  67
  68 extern  struct nfs_page *nfs_create_request(struct nfs_open_context *ctx,
  69                                             struct inode *inode,
  70                                             struct page *page,
  71                                             unsigned int offset,
  72                                             unsigned int count);
  73 extern  void nfs_clear_request(struct nfs_page *req);
  74 extern  void nfs_release_request(struct nfs_page *req);
  75
  76
  77 extern  int nfs_scan_list(struct nfs_inode *nfsi, struct list_head *dst,
  78                           pgoff_t idx_start, unsigned int npages, int tag);
  79 extern  void nfs_pageio_init(struct nfs_pageio_descriptor *desc,
  80                              struct inode *inode,
  81                              int (*doio)(struct inode *, struct list_head *, unsigned int, size_t, int),
  82                              size_t bsize,
  83                              int how);
  84 extern  int nfs_pageio_add_request(struct nfs_pageio_descriptor *,
  85                                    struct nfs_page *);
  86 extern  void nfs_pageio_complete(struct nfs_pageio_descriptor *desc);
  87 extern  void nfs_pageio_cond_complete(struct nfs_pageio_descriptor *, pgoff_t);
  88 extern  int nfs_wait_on_request(struct nfs_page *);
  89 extern  void nfs_unlock_request(struct nfs_page *req);
  90 extern  int nfs_set_page_tag_locked(struct nfs_page *req);
  91 extern  void nfs_clear_page_tag_locked(struct nfs_page *req);
  92
  93
  94 /*
  95  * Lock the page of an asynchronous request without getting a new reference
  96  */
  97 static inline int
  98 nfs_lock_request_dontget(struct nfs_page *req)
  99 {
 100         return !test_and_set_bit(PG_BUSY, &req->wb_flags);
 101 }
 102
 103 /**
 104  * nfs_list_add_request - Insert a request into a list
 105  * @req: request
 106  * @head: head of list into which to insert the request.
 107  */
 108 static inline void
 109 nfs_list_add_request(struct nfs_page *req, struct list_head *head)
 110 {
 111         list_add_tail(&req->wb_list, head);
 112 }
 113
 114
 115 /**
 116  * nfs_list_remove_request - Remove a request from its wb_list
 117  * @req: request
 118  */
 119 static inline void
 120 nfs_list_remove_request(struct nfs_page *req)
 121 {
 122         if (list_empty(&req->wb_list))
 123                 return;
 124         list_del_init(&req->wb_list);
 125 }
 126
 127 static inline struct nfs_page *
 128 nfs_list_entry(struct list_head *head)
 129 {
 130         return list_entry(head, struct nfs_page, wb_list);
 131 }
 132
 133 static inline
 134 loff_t req_offset(struct nfs_page *req)
 135 {
 136         return (((loff_t)req->wb_index) << PAGE_CACHE_SHIFT) + req->wb_offset;
 137 }
 138
 139 #endif /* _LINUX_NFS_PAGE_H */